1. Field of the Invention
The present invention relates to telecommunication systems, and in particular, to caller name delivery services and networks that track the location and identity of network devices.
2. Background of the Invention
Users of modern public switched telephone networks (PSTNs) have long enjoyed the benefits of calling name delivery (CNAM), also known as caller identification or caller ID. CNAM enables a called party to view information about a calling party on a display unit, which is typically a liquid crystal display (LCD), a light-emitting diode (LED) display, or a comparable device. The displayed information generally includes at least the calling party's name, the calling party's directory number, and the date and time of the call.
PSTNs typically provide CNAM information (except for the date and time, which is generally provided by the display unit) using the model illustrated in FIG. 1, which is a prior art schematic of a CNAM system architecture implemented within an Advanced Intelligent Network (AIN). AIN networks use a complex, high speed, high traffic volume data packet-switched messaging system to provide versatility in the handling of telephone calls. The Advanced Intelligent Network System is described in U.S. Pat. No. 5,701,301 and U.S. Pat. No. 5,838,774, which are hereby incorporated by reference in their entirety.
Referring to FIG. 1, CNAM is typically implemented in the following manner. A calling party 101 picks up the telephone and dials the directory number of a called party 102, which is 404-555-2222. Called party 102 is a CNAM subscriber having a CNAM display unit 116. CNAM display unit 116 could be separate from or integral to the device of called party 102. After calling party 101 dials the directory number, an central office 104 (also referred to as a service switching point) serving calling party 101 obtains routing information and populates an initial address message (IAM) with certain information. The IAM is a parameter that exists within an integrated services digital network user part (ISUP) signaling message. The IAM is a defined message type from TR-NTW-000246 and ITU Q.764/Q.767, and is one of a sequence of messages used in ISUP trunk signaling. An ISUP signaling message employs a Common Circuit Signaling System 7 (CCS7) call setup protocol. In particular, the IAM is populated with the directory number of calling party (404-555-1111), the directory number of the called party (404-555-2222), and a presentation parameter. In this case, the presentation parameter allows a CNAM display.
Central office 104 then sends this routing information in the signaling message to a central office 106, which serves called party 102. Recognizing that the call is for a CNAM subscriber, central office 106 halts the calling process to launch a calling name query 150 on the CCS7 network. As a part of the query launch, central office 106 populates a called party address parameter in query 150 with the directory number of calling party 101, in this case 404-555-1111. The called party address parameter is a routing parameter within an Advanced Intelligence Network (AIN) query package.
After central office 106 has populated the called party address parameter, calling name query 150 is sent to a signaling transfer point (STP) 108. STP 108 performs a global title translation (GTT) on the called party address parameter to determine to which service control point (SCP) calling name query 150 should be routed. This determination is made based on the first three digits (the numbering plan area, or NPA) in the directory number of calling party 101, which in this case is 404. STP 108 then forwards the calling name query to the appropriate SCP 112 through CCS7 Network 110. SCP 112 searches a CNAM database 114 for calling party's record from which SCP 112 retrieves the associated name. CNAM database 114 is preferably a part of SCP 112, as shown in FIG. 1, but may be separate from SCP 112, or incorporated as part of another network element such as a service node or a switch.
SCP 112 returns the name associated with the directory number of calling party 101 in a transaction capability application part (TCAP) response 151 to central office 106 through CCS7 Network 110 and STP 108. TCAP response 151 is the final message containing instructions on how to handle the call. TCAP response 151 ends the SSP/SCP transaction that began with calling name query 150. In this example, the full name of calling party 101 is returned in TCAP response 151 to central office 106.
When central office 106 terminates the call to called party 102, central office 106 sends the name of calling party 101 and the directory number of calling party 101 (404-555-1111). Central office 106 sends this information over called party's line to called party's display unit 116. The information is then displayed on called party's display unit 116, along with the date and time of the call (generated by display unit 116).
The principal advantage of conventional CNAM services is the ability to screen calls. Upon receiving a call, a called party can review the information on the display unit and decide whether or not to answer the call. However, users wanting to screen calls and fulfill other location-sensitive purposes often prefer to know more about the calling party than just name, number, date, and time. For instance, a service dispatcher monitoring the activities of his service technician may wish to receive the exact location of his technician each time the technician calls in, so as to facilitate efficient scheduling of the next assignment. Although the name and number on the CNAM display unit could possibly provide clues to the technician's location, the dispatcher would prefer seeing a more precise and easily understandable description of location, e.g., a street address or building name. Thus, although the typical CNAM information may be suitable for simple call screening, many telephone users would prefer to receive even more information about the calling party.